1. Field of the Invention
The invention generally relates to a hydraulic pressure system associated with a motor vehicle torque coupling. Specifically, the invention relates to an integral housing for a gerotor pump and associated accumulator.
2. Background of the Invention
The prior art includes various systems for developing hydraulic pressure to provide power to equipment associated with the hydraulic system of a motor vehicle, such as hydraulically actuated torque coupling assemblies. Vehicle torque coupling assemblies typically include a hydraulic pump and an accumulator. When the hydraulic pump is energized, pressurized fluid is selectively supplied into the vehicle hydraulic system, including the accumulator reservoir. As the hydraulic system is further pressurized, the volume of the accumulator reservoir expands, thereby compressing a gas charge or a resilient member (usually a spring) associated with the accumulator reservoir. When the pump is turned off, the hydraulic pressure within the accumulator reservoir is maintained through pressure applied by the gas charge or resilient member. The fluid within the accumulator reservoir communicates the hydraulic pressure to the other parts of the hydraulic system, thereby ensuring that the hydraulic system is pressurized when the vehicle hydraulic pump is not operating.
Vehicle hydraulic pumps have a variety of designs including reciprocating piston-type pumps, centrifugal pumps, and gerotor pumps. Hydraulic gerotor pumps are generally preferred in applications associated with torque couplings, including limited slip differentials. Gerotor pumps are typically built into the torque coupling assemblies and housed within the torque coupling housing. The associated accumulator is conventionally mounted to a body or frame member of the motor vehicle. Since the hydraulic pump is the source of hydraulic pressure when the pump is activated, and the accumulator is the source of hydraulic pressure when the pump is inactive, an extensive and redundant system of hydraulic pressure lines is needed to support both sources of hydraulic pressure.
While known hydraulic couplings, including but not limited to those discussed above, have proven to be acceptable for various vehicular driveline applications, such devices are nevertheless susceptible to improvements that may enhance their performance, cost and simplify both the hydraulic system and the torque coupling design. With this in mind, a need exists to develop improved hydraulic torque-coupling assemblies that advance the art.